The orbital alignment at poly[2-methoxy-5- (2′ -ethylhexyloxy)- p -phenylene vinylene (MEH-PPV) interfaces to Au and highly oriented pyrolytic graphite (HOPG) was investigated using x-ray and ultraviolet photoemission spectroscopies in combination with in situ multistep electrospray based thin film deposition. The electrospray deposition method enables deposition of polymers in vacuum directly from solution. This allows the investigation of polymer interfaces without the use of spin coating. Hence interfaces without the presence of significant contamination can be prepared, similar to what is possible at small molecular interfaces using in-vacuum evaporation. The presented experiments suggest, in conjunction with earlier experiments on MEH-PPV/Ag and MEH-PPV/indium tin oxide interfaces, that the currently assumed vacuum level alignment at conjugated polymer interfaces may not hold in all cases.
Bibliographical noteFunding Information:
Financial support by the National Science Foundation (Grant Nos. DMR 0205577 and DMR 0510000) is gratefully acknowledged. One of the authors (Y.Y.) acknowledges financial support from the IT Scholarship Program supervised by the Institute for Information Technology Advancement (IITA) and the Ministry of Information and Communication (MIC) of the Republic of Korea.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)